Electric twin flow pump apparatus

ABSTRACT

An electric twin flow pump apparatus configured to include a housing wherein a transmission oil passage and a water jacket are separately formed; a motor wherein one side of the housing is mounted and its drive shaft passes through the oil passage and water jacket and extends to the other side of the housing; a first impeller that is coaxially secured at the drive shaft and located in the water jacket path; and a second impeller that is coaxially secured at the drive shaft and located in the oil passage so as to provide a twin flow pump that has formed an electric oil pump and an electric water pump as one body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of Korean Application No. 10-2003-0081838, filed Nov. 18, 2003, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

This invention relates to pumps for vehicles, and more specifically to an electric twin flow pump apparatus including an electric water pump and an electric oil pump.

(b) Description of the Related Art

In general, a 14V power system uses vehicles, and the maximum power that may be supplied by a 14V power system is known to be approximately 2.5 KW. However, a number of various electric and electronic equipment of new technologies are recently mounted in a vehicle, and the said 14V power system cannot supply a stable voltage to the new equipment. Therefore, a power system whose battery voltage has been boosted to a high voltage of 24V or higher (for example, 35V or 42V) has been recently researched.

In the case of the 42V vehicle, an idle stop mode has been adopted as a method to prevent air pollution and reduce fuel consumption. The idle stop is a function that does not place an engine in an idle condition but stops it if a vehicle stops. Specifically, the engine is automatically stopped based on a signal concerning the vehicle speed from a vehicle speed sensor without manipulating an ignition switch. The engine is re-started based on a signal from the accelerator pedal sensor that detects manipulation of an accelerator pedal, and emission of air pollution materials such as carbon dioxide may be suppressed.

However, the engine stops under the condition of idle stop, and, as a result, it becomes impossible to drive a peripheral device that is driven by belt driving of an engine, for example a transmission oil pump. On the other hand, if an engine is restarted under the condition of idle stop, it becomes necessary to input oil into a transmission to prevent a change speed shock in the transmission. Therefore, usage of an electric oil pump is being considered that may be driven under the condition of idle stop.

In addition, an additional sub-cooling system is configured for the 42V vehicle to cool down peripheral devices following adoption of a 42V power system. Thus, a water pump to be used needs to be installed with an electric pump as well.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a twin flow pump in which an electric oil pump and an electric water pump are formed as one body. In a preferred embodiment, an electric twin flow pump apparatus according to this invention includes a housing wherein a transmission oil passage and a water jacket are separately formed; a motor wherein one side of the housing is mounted and its drive shaft passes through the oil passage and water jacket and extends to the other side of the housing; a first impeller that is coaxially secured at the drive shaft and located in the water jacket path; and a second impeller that is coaxially secured at the drive shaft and located in the oil passage.

In an alternative embodiment, an electric twin flow pump apparatus according to this invention includes a housing wherein a transmission oil passage and a water jacket are separately formed; a motor wherein it is interposed between the oil passage and the water jacket and mounted at the housing, but its drive shaft passes through the oil passage and the water jacket and extends to both ends of the housing; a first impeller that is coaxially secured at the drive shaft and located in the water jacket path; and a second impeller that is coaxially secured at the drive shaft and located in the oil passage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing illustrating a configuration of an electric twin flow apparatus according to a first embodiment of this invention;

FIG. 2 is a schematic drawing illustrating a configuration of the electric twin flow pump apparatus according to a second embodiment of this invention;

FIG. 3 is a graph illustrating operating conditions of an electric twin flow pump apparatus concerning cooling water temperatures; and

FIG. 4 is a graph illustrating operating conditions of an electric twin flow pump apparatus concerning the idle stop.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following describes the embodiments of this invention in reference to the drawings attached.

FIG. 1 illustrates a configuration of an electric twin flow pump apparatus of a 42V vehicle according to a first embodiment of this invention. As illustrated in FIG. 1, a water jacket (110) and an oil passage (120) are respectively formed in the housing of the electric twin flow pump (100). Each forms a chamber on a common axis for containing an impeller. A motor (200) is mounted in one side of the housing (100). A drive shaft (210) of the motor (200) passes through the water jacket (110) and the oil passage (120) and extends to the other side of the housing (100). The motor (200) includes a coil (230) and a rotor (220), and the drive shaft (210), if a power source is applied to a coil, rotates with the rotor (220). Preferably, a bearing (300) is furnished on the other side of the housing (100) and supports the drive shaft (210) extended.

A first impeller (400) is coaxially secured at the location where it passes through the water jacket (110) of the drive shaft (210). A second impeller (500) is coaxially secured on the drive shaft (210) at the location where it passes through the oil passage (120) of the drive shaft (210). Furthermore, a sealing member (610, 620) is mounted in the housing (100) to prevent cooling water or oil from leaking outside the housing.

Examining the water jacket (110) and the oil passage (120) in detail, the water jacket (110) forms a passage for cooling water of a cooling water system that has been additionally configured to cool down peripheral devices following adoption of a 42V power system. Cooling water flows in the cooling water system to cool down MCU, DC/DC converter, inverter, etc. In addition, the oil passage (120) is a passage for oil supplied to a transmission to prevent change speed shock of a transmission at the idle stop mode of an engine and when idle stop condition is changed to an operation condition.

FIG. 2 illustrates a configuration of an electric twin flow pump apparatus of a 42V vehicle according to a second embodiment of this invention. In this embodiment, the location of motor (200 a) mounted on a housing (100 a) has been changed; however, the housing still defines two impeller chambers on a common axis. Comparing this with the prior embodiment, motor (200 a) is mounted at the center of housing (100 a). Drive shaft (210 a, 210 b) of motor (200 a) is extended to both ends of a housing (100 a) in this embodiment. In addition, the drive shafts (210 a, 210 b) extending to both ends of the housing (100) have a structure that is supported respectively by bearings (300 a, 300 b) so as to allow rotation. Therefore, it has the shape that a water jacket (110 a) and an oil passage (120 a) are located at both sides centering on the motor (100 a).

If the motor is driven, the first impeller and the second impeller coaxially secured at the drive shaft begin to rotate, and cooling water and oil is forced to circulate. If the temperature of cooling water exceeds the temperature setting, the motor operates based on the temperature, or, if the idle stop condition of an engine is changed to an operation condition, it is driven to supply oil of the hydraulic pressure setting to a transmission. The cooling water temperature condition that requires supply of the cooling water and the idle stop condition that requires supply of the oil may not be satisfied at the same time, so the motor is controlled based on one of the two conditions.

FIG. 3 is a graph concerning the cooling water condition under which the motor is driven. As illustrated in FIG. 3, the motor is driven if the temperature of cooling water exceeds 53° C., and, if the first impeller is rotated by driving the motor, cooling water cools down peripheral devices of a 42V system circulating a cooling system.

On the other hand, in FIG. 4 is a graph concerning the idle stop mode under which the motor is driven. As illustrated in FIG. 4, if the supply of oil with an oil setting is required, it marks the idle stop condition and the time at which an idle stop mode is changed to an operation condition. Afterward, oil supply takes place by a mechanical oil pump.

Based on the transmission fluid pressure curve illustrated in FIG. 4, the motor (200) is driven as low duty at an idle stop mode and as high duty when an idle stop mode is changed to an operation condition to rotate the second impeller.

It is self-evident that the second embodiment may also be controlled by the same method of the first embodiment, so further explanation is omitted. According to the electric twin flow pump apparatus based on this invention, it provides a twin flow pump that has formed an electric oil pump and an electric water pump as one body to promote reduction of a number of parts and simplification of a structure. 

1. An electric twin flow pump apparatus, comprising: a housing wherein a transmission oil passage and a water jacket are separately formed; a motor wherein one side of the housing is mounted with a drive shaft passing through the oil passage and water jacket and extending to an opposite side of the housing; a first impeller that is coaxially secured on the drive shaft and located in the water jacket; and a second impeller that is coaxially secured on the drive shaft and located in the oil passage.
 2. The electric twin flow pump apparatus according to claim 1, wherein the motor is driven if the temperature of the cooling water exceeds a temperature setting or if an associated engine is in the idle stop mode.
 3. The electric twin flow pump apparatus according to claim 2, wherein bearings are further included in the opposite side of the housing that supports the drive shaft.
 4. The electric twin flow pump apparatus according to claim 3, wherein one or more sealing members are furnished in the housing.
 5. The electric twin flow pump apparatus according to claim 4, wherein the motor is furnished as a DC motor.
 6. An electric twin flow pump apparatus, comprising: a housing wherein a transmission oil passage and a water jacket are separately formed; a motor interposed between the oil passage and the water jacket and mounted at the housing with a drive shaft passing through the oil passage and the water jacket and extending to both ends of the housing; a first impeller that is coaxially secured on the drive shaft and located in the said water jacket; and a second impeller that is coaxially secured on the drive shaft and located in the oil passage.
 7. The electric twin flow pump apparatus according to claim 6, wherein the motor is driven if the temperature of the cooling water exceeds a temperature setting or if an associated engine is in the idle stop mode.
 8. The electric twin flow pump apparatus according to claim 7, wherein bearings are further included that support the drive shaft of the motor to enable its rotation at both ends of the housing.
 9. The electric twin flow pump apparatus according to claim 8, wherein one or more sealing members are furnished in the housing.
 10. The electric twin flow pump apparatus according to claim 9, wherein the motor is furnished as a DC motor.
 11. An electric twin flow pump apparatus, comprising: a housing including separately a formed transmission oil passage and water jacket, wherein said oil passage and water jacket each define an impeller chamber formed around a common axis; a first impeller disposed in the water jacket impeller chamber configured and dimensioned for pumping water; a second impeller disposed in the oil passage impeller chamber configured and dimensioned for pumping transmission oil; at least one drive shaft extending between said impellers along said common axis for driving said impellers; and a motor operatively connected to said at least one drive shaft.
 12. The pump apparatus of claim 11, wherein said motor is disposed to one side of said housing and a single drive shaft extends from the motor through one impeller to the other impeller.
 13. The pump apparatus of claim 12, further comprising a shaft supporting bearing mounted on the housing opposite said motor.
 14. The pump apparatus of claim 11, wherein said motor is disposed between said impeller chambers and drive shafts extend from opposite sides of the motor to the first and second impellers.
 15. The pump apparatus of claim 14, further comprising first and second shaft supporting bearings mounted on opposite sides of said impeller chambers from said motor. 